This invention generally relates to intravascular catheters, such as balloon dilatation catheters used in percutaneous transluminal coronary angioplasty (PTCA).
PTCA is a widely used procedure for the treatment of coronary heart disease wherein a balloon dilatation catheter is advanced into the patient's coronary artery and the balloon on the distal portion of the catheter is inflated within the stenotic region of the patient's artery to open up the arterial passageway and thereby increase the blood flow therethrough. To facilitate the advancement of the dilatation catheter into the patient's coronary artery, a guiding catheter having a preshaped distal tip is first percutaneously introduced into the cardiovascular system of a patient by the Seldinger technique through the brachial or femoral arteries and is advanced therein until the preshaped distal tip of the guiding catheter is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from its proximal end, which extends out of the patient, to guide the distal tip of the guiding catheter into the desired ostium. A balloon dilatation catheter may then be advanced through the inner lumen of the guiding catheter into the patient's coronary artery until the balloon on the dilatation catheter is disposed within the stenotic region of the patient's artery. The balloon is inflated and deflated one or more times to open up the arterial passageway and increase the flow of blood.
One type of catheter frequently used in PTCA procedures is an over-the-wire type balloon dilatation catheter. Commercially available over-the-wire type dilatation catheters include the SIMPSON ULTRA LOW PROFILE (TM), the HARTZLER ACX (R), the HARTZLER ACX II (TM), the PINKERTON 0.018 (TM) and the-ACS TEN (TM) balloon dilatation-catheters sold by the assignee of the present invention, Advanced Cardiovascular Systems, Inc. (ACS).
Another type of over-the-wire dilatation catheter is the rapid exchange type catheter, which was introduced by ACS. under the trademark ACS RX.RTM. Coronary Dilatation Catheter. It is described and claimed in U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock), U.S. Pat. No. 4,748,982 (Horzewski et al.) and U.S. Pat. No. 5,154,725 (Leopold) which are incorporated herein by reference. This dilatation catheter has a short guidewire receiving sleeve or inner lumen extending through a distal portion of the catheter. The sleeve or inner lumen extends proximally from a first guidewire port in the distal end of the catheter to a second guidewire port in the catheter spaced proximally from the inflatable member of the catheter. A slit may be provided in the wall of the catheter body which extends distally from the second guidewire port, preferably to a location proximal to the proximal end of the inflatable balloon. The structure of the catheter allows for the rapid exchange of the catheter without the need for an exchange wire or adding a guidewire extension to the proximal end of the guidewire.
Some over-the-wire and rapid exchange type dilatation catheters have perfusion capabilities where one or more perfusion ports are provided in the catheter shaft proximal to the dilatation balloon which are in fluid communication with a guidewire receiving inner lumen extending to the distal end of the catheter. Additionally, one or more perfusion ports are preferably provided in the catheter shaft, distal to the balloon which are also in fluid communication with the guidewire receiving inner lumen. When the balloon of a dilatation catheter with perfusion capabilities is inflated to dilate a stenosis, oxygenated blood in the artery or the aorta or both, depending upon the location of the proximal perfusion parts of the dilatation catheter within the coronary anatomy, is forced to pass through the proximal perfusion ports, through the guidewire receiving inner lumen of the catheter and out the distal perfusion ports. The flow of oxygenated blood downstream from the inflated balloon minimizes ischemic conditions in tissue distal to the balloon and allows for long term dilatations, e.g. 30 minutes or even several hours or more. Commercially available perfusion type dilatation catheters include the STACK PERFUSION (TM) and the ACS RX PERFUSION (TM) dilatation catheters which are sold by ACS.
A continual effort has been made in the development of intravascular catheters, particularly angioplasty catheters, to reduce the transverse dimensions or profile of such catheters and the flexibility without detrimentally affecting the pushability and other characteristics of the catheters, particularly in the distal portion of the catheters which are advanced through tortuous anatomy. A balloon dilatation catheter with an increased flexibility and an Increased pushability allow the catheter to be advanced much further Into a patient's vasculature and to cross much tighter lesions.
Despite the many technical advances in these areas, the need for intravascular catheters having even greater flexibility and pushability remains. The present invention satisfies these and other needs.